STUDY OF SOUND SOURCE IDENTIFICATION BASED ON BEAMFORMING AND PATCH NEAR-FIELD ACOUSTIC HOLOGRAPHY

2009 ◽  
Vol 17 (03) ◽  
pp. 219-245 ◽  
Author(s):  
WENQIANG JIA ◽  
JIN CHEN ◽  
CHAO YANG ◽  
JIAQING LI
Keyword(s):  
Regularization Parameter ◽  
Near Field ◽  
Sound Field ◽  
Reconstruction Error ◽  
Tikhonov Regularization Method ◽  
Superposition Method ◽  
Sound Sources ◽  
Extrapolation Technique ◽  
Measurement Surface ◽  
Data Extrapolation

A study for applying data extrapolation technique based on wave superposition method (WSM) is proposed to overcome the disadvantages of near-field acoustical holography (NAH). Unlike conformal NAH, where the measurement surface surrounds the entire structure, in the patch holography the measurement surface needs only be approximately as large as the patch on the structure surface where the reconstruction is required. At first, a microphone array is used to acquire the sound pressure field radiated from a vibrator; then a beamforming method is adopted to locate sound sources; after that, a serial of equivalent sources are collocated around these sound sources; at last, a data extrapolation technique based on WSM is applied to extend the measurement aperture and reconstruct the sound field. Since the data extrapolation algorithm requires the inversion of Green's function matrix which may be ill-conditioned, Tikhonov regularization method is used to invert it, and the value of the regularization parameter is determined by the L-curve criteria. The effectiveness of this method is demonstrated by numerical simulation with two pulse ball model, and also experiment is carried out in a semi-anechoic chamber using two sound boxes. The results confirm that the exterior sound field can be accurately reconstructed with few iterative times and the reconstruction error is sufficiently suppressed by the proposed method.

Study of a sound field separation technique based on a single holographic surface and wave superposition method

2009 ◽  
Vol 223 (8) ◽  
pp. 1827-1836
Author(s):  
W Q Jia ◽  
J Chen ◽  
C Yang ◽  
Z Y Wang
Keyword(s):  
Sound Pressure ◽  
Regularization Parameter ◽  
Sound Field ◽  
Mirror Image ◽  
Separation Technique ◽  
Tikhonov Regularization Method ◽  
Superposition Method ◽  
Wave Superposition ◽  
Measurement Surface ◽  
Field Separation

In order to overcome the limitation of traditional near-field acoustical holography (NAH), that the sound field on one side of the holographic surface must be free, a sound field separation technique based on single holographic surface and wave superposition method (WSM) is proposed. According to the WSM, the field on and near the measurement surface may be approximated by the field produced by virtual source points placed on a surface inside the structure. The source strengths are evaluated by applying boundary conditions on the measurement surface. Here, the ‘pseudo’ sound pressure of the reconstruction surface is first obtained based on the principle of sound field mirror image and WSM, then the sound pressure of the target sound source acting on the holographic surface is separated by the sound pressures of the holographic surface and the reconstruction surface, and the sound field separation is realized. The technique requires the inversion of the Green's function matrix, which may be ill-conditioned. The Tikhonov regularization method is used to invert it, and the value of the regularization parameter is determined by the L-curve criteria. Through the numerical simulation and experiment, the results show the validity and efficiency of this technique.

Sound field separation of multiple coherent sound sources with single measurement surface

2021 ◽  
pp. 107754632110201
Author(s):  
Jin Mao ◽  
Jinfu Du ◽  
Kai Liu ◽  
Jiang Liu ◽  
Yahui Cui
Keyword(s):  
Near Field ◽  
Sound Field ◽  
Single Measurement ◽  
Sound Sources ◽  
Equivalent Source ◽  
Coherent Sources ◽  
Measurement Surface ◽  
Acoustical Holography ◽  
Field Separation ◽  
Source Number

Sound field separation based on near-field acoustical holography has been developed worldwide, but with the increase in the number of sound sources, traditional measurement methods and calculation methods will generate more workload. To reduce the number of measuring points and save calculation time, the sound field separation of multiple coherent sources with a single measurement surface is proposed. On the basis of separating two coherent sources with this method, the separation formula of more sources based on an equivalent source method is given. Through numerical simulation, the effects of the number of holographic surface measuring points, measuring distance, array shape, and equivalent source number on the calculation accuracy of the sound field separation were compared at different frequencies. The correctness and effectiveness of the sound field separation method with a single surface are verified by actual experiments.

Sound Source Identification and Acoustic Contribution Analysis Using Nearfield Acoustic Holography

2014 ◽  
Vol 945-949 ◽  
pp. 717-724 ◽  
Author(s):  
Jiang Hua Deng ◽  
Jun Hong Dong ◽  
Guang De Meng
Keyword(s):  
Source Identification ◽  
Noise Source ◽  
Near Field ◽  
Superposition Principle ◽  
Sound Field ◽  
Mirror Image ◽  
Sound Sources ◽  
Incoming Wave ◽  
Reflected Waves ◽  
Acoustic Contribution

The main goal of the present paper is to provide a method of source identification. Firstly, statistically optimal near-field acoustical holography (SONAH) techniques are applied to locate sound sources with the reflected sound field. In the presence of reflection plane parallel and perpendicular to the source plane, the incoming wave and reflected waves are separated based on the acoustic superposition principle and acoustic mirror image principle to satisfy the condition of the sound sources reconstruction using SONAH. Secondly, contribution of noise source to the special field point is analyzed and noise source ranking of interior panel groups are evaluated based the proposed three step acoustic contribution method. Finally, this method is verified experimentally.

Near Field Acoustic Holography for Cyclostationary Sound Field and its Partial Source Decomposition Procedure

2005 ◽  
Vol 127 (6) ◽  
pp. 542-546 ◽  
Author(s):  
Quan Wan ◽  
W. K. Jiang
Keyword(s):  
Principal Component Analysis ◽  
Sound Pressure ◽  
Near Field ◽  
Sound Field ◽  
Principal Component ◽  
Acoustic Holography ◽  
Sound Sources ◽  
Decomposition Procedure ◽  
Spectrum Density ◽  
Simulation Results

The cyclostationary near field acoustic holography (NAH) technique is proposed to overcome the limitations of the current NAH in analyzing cyclostationary sound field. The proposed technique adopts the cyclic spectrum density as the reconstructed physical quantity, instead of the spectrum of sound pressure. Moreover, introducing the principal component analysis into the technique, a partial source decomposition procedure is suggested to decompose the sound field radiated by multiple sound sources into some incoherent partial fields. More information about cyclostationary sound field can be shown clearly on the hologram of the proposed technique than NAH can, which is validated by the simulation results.

Simulation and experimental investigations for the patch near-field acoustical holography

2008 ◽  
Vol 222 (6) ◽  
pp. 945-953 ◽  
Author(s):  
C Yang ◽  
J Chen ◽  
J Q Li ◽  
W F Xue
Keyword(s):  
Fourier Transform ◽  
Sound Pressure ◽  
Near Field ◽  
Sound Field ◽  
Experimental Investigations ◽  
Regularization Methods ◽  
Aperture Size ◽  
Measurement Surface ◽  
Physical Necessity ◽  
Acoustical Holography

In order to reconstruct the sound field, the fast Fourier transform (FFT)-based near-field acoustical holography (NAH) demands that the measurement surface must extend to a region where the sound pressure decreases to a low level. This method is unfit for reconstructing the partial sound field in which the measurement aperture size is limited either by physical necessity or as a way of reducing the measurement cost. Statistically optimal NAH (SONAH) performs plane-to-plane calculations directly in the spatial domain, avoids all errors occurred in the FFT-based NAH and significantly increases the accuracy of the reconstruction of the partial sound field. In the present work, combined with the different regularization methods, SONAH is performed for reconstructing the partial sound field. The errors over the central and the peripheral sections of the reconstruction area are researched separately. Simulations and experiments show that SONAH is successful in reconstructing the partial sound field and the errors over the central sections are smaller than that over the peripheral sections. Experiments demonstrate that Tikhonov regularization in conjunction with Engl's criterion is suitable for the reconstruction of the practical sound field.

Active Control of Low-Frequency Sound Radiation From Vibrating Panel Using Planar Sound Sources

2001 ◽  
Vol 124 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Kean Chen ◽  
Gary H. Koopmann
Keyword(s):  
Active Control ◽  
Near Field ◽  
Low Frequency ◽  
Sound Radiation ◽  
Sound Field ◽  
Sound Power ◽  
Frequency Range ◽  
Sound Sources ◽  
Frequency Sound ◽  
Secondary Sources

Active control of low frequency sound radiation using planar secondary sources is theoretically investigated in this paper. The primary sound field originates from a vibrating panel and the planar sources are modeled as simply supported rectangular panels in an infinite baffle. The sound power of the primary and secondary panels are calculated using a near field approach, and then a series of formulas are derived to obtain the optimum reduction in sound power based on minimization of the total radiate sound power. Finally, active reduction for a number of secondary panel arrangements is examined and it is concluded that when the modal distribution of the secondary panel does not coincide with that of the primary panel, one secondary panel is sufficient. Otherwise four secondary panels can guarantee considerable reduction in sound power over entire frequency range of interest.

Reconstruction of Interior Sound Fields of Vibrating Shells with an Open Spherical Microphone Array

2016 ◽  
Vol 24 (04) ◽  
pp. 1650013 ◽  
Author(s):  
Minzong Li ◽  
Huancai Lu
Keyword(s):  
Cross Validation ◽  
Microphone Array ◽  
Sound Field ◽  
Reconstruction Error ◽  
Wave Number ◽  
Tikhonov Regularization Method ◽  
Sound Fields ◽  
Noise Regularization ◽  
Enclosed Space ◽  
The Impact

Spherical acoustic holography was utilized to reconstruct the interior sound field of an enclosed space with vibrating boundaries using an open spherical microphone array. The interior sound fields of vibrating shells, including a pulsating shell, a [Formula: see text]-axis oriented oscillating shell, a partially vibrating shell and a point-excited vibrating shell, were reconstructed, and numerical simulations were carried out to examine the impact of reconstruction parameters, the radius of the microphone array, the number of microphones, the distribution of microphones on the array surface, the wave number, the number of basis functions used, and the radius of the reconstruction surface on the accuracy of reconstruction. In order to minimize the error of reconstruction caused by a variety of factors and uncertainties, such as the measurement noise, regularization treatments were introduced into the process of reconstructing, to suppress the divergent trends of the reconstruction error along with the increase of the wave number and the increase of the radius of the reconstruction surface. Results showed that a Tikhonov regularization method with generalized cross validation (GCV) could yield the least error of reconstruction among the investigated regularization methods.

Study of Spherical Near-Field Acoustic Holography with Rigid Spherical Microphone Array

2013 ◽  
Vol 546 ◽  
pp. 156-163
Author(s):  
Xin Guo Qiu ◽  
Ming Zong Li ◽  
Huan Cai Lu ◽  
Wei Jiang
Keyword(s):  
Sound Source ◽  
Microphone Array ◽  
Near Field ◽  
Sound Field ◽  
Acoustic Holography ◽  
Real Situation ◽  
Helmholtz Equations ◽  
Sound Sources ◽  
Array Configuration ◽  
Sphere Radius

The aim of this paper is to investigate the impacts of various parameters of rigid spherical microphone array in detecting and locating interior sound source. Helmholtz Equations are adopted to express the sound field produced by the incident field and scattered field. The gradient of the pressure is zero at the surface for the sphere is rigid. Both the incident and scattered coefficient could be obtained by solving the Helmholtz Equation using the boundary condition. Then the interior sound field could be detected and located on with the methodology of spherical near-field acoustic holography (SNAH). This study is developed in two aspects，one is configuring the microphone in various distribution in the same sphere radius, and the other one is changing the radius of sphere array. Numerical simulations are carried out to determine the optimum microphone array configuration and structure parameters. One, two, and three sound sources are arranged respectively in different displacement to the sphere center and in different angle direction to simulate the real situation. During the experiments, Omni-directional speakers and beeps are adopted as sound sources. The result shows that the method to detect and locate sound source in interior sound field is valid.

scholarly journals A New Method for Determining Optimal Regularization Parameter in Near-Field Acoustic Holography

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Yue Xiao
Keyword(s):  
Point Source ◽  
Regularization Parameter ◽  
Near Field ◽  
New Method ◽  
Tikhonov Regularization Method ◽  
Acoustic Holography ◽  
Reconstruction Process ◽  
Curve Method ◽  
Univariate Optimization ◽  
Equivalent Sources

Tikhonov regularization method is effective in stabilizing reconstruction process of the near-field acoustic holography (NAH) based on the equivalent source method (ESM), and the selection of the optimal regularization parameter is a key problem that determines the regularization effect. In this work, a new method for determining the optimal regularization parameter is proposed. The transfer matrix relating the source strengths of the equivalent sources to the measured pressures on the hologram surface is augmented by adding a fictitious point source with zero strength. The minimization of the norm of this fictitious point source strength is as the criterion for choosing the optimal regularization parameter since the reconstructed value should tend to zero. The original inverse problem in calculating the source strengths is converted into a univariate optimization problem which is solved by a one-dimensional search technique. Two numerical simulations with a point driven simply supported plate and a pulsating sphere are investigated to validate the performance of the proposed method by comparison with the L-curve method. The results demonstrate that the proposed method can determine the regularization parameter correctly and effectively for the reconstruction in NAH.

scholarly journals A modified Tikhonov regularization method based on Hermite expansion for solving the Cauchy problem of the Laplace equation

2020 ◽  
Vol 18 (1) ◽  
pp. 1685-1697
Author(s):  
Zhenyu Zhao ◽  
Lei You ◽  
Zehong Meng
Keyword(s):  
Cauchy Problem ◽  
Laplace Equation ◽  
Tikhonov Regularization ◽  
Regularization Method ◽  
Regularization Parameter ◽  
Solution Process ◽  
Tikhonov Regularization Method ◽  
Hermite Expansion ◽  
The Cauchy Problem ◽  
Ill Posed

Abstract In this paper, a Cauchy problem for the Laplace equation is considered. We develop a modified Tikhonov regularization method based on Hermite expansion to deal with the ill posed-ness of the problem. The regularization parameter is determined by a discrepancy principle. For various smoothness conditions, the solution process of the method is uniform and the convergence rate can be obtained self-adaptively. Numerical tests are also carried out to verify the effectiveness of the method.

Sign in / Sign up

Export Citation Format

Share Document